35,245 research outputs found
Adolescent D-amphetamine treatment in a rodent model of ADHD: pro-cognitive effects during adolescence and cocaine abuse risk during adulthood
Attention-deficit/hyperactivity disorder (ADHD) is comorbid with cocaine abuse. Whereas initiating ADHD medication in childhood does not alter later cocaine abuse risk, initiating medication during adolescence may increase risk. Preclinical work in the Spontaneously Hypertensive Rat (SHR) model of ADHD found that adolescent methylphenidate increased cocaine self-administration in adulthood, suggesting a need to identify alternatively efficacious medications for teens with ADHD. We examined effects of adolescent d-amphetamine treatment on strategy set shifting performance during adolescence and on cocaine self-administration and reinstatement of cocaine-seeking behavior (cue reactivity) during adulthood in male SHR, Wistar- Kyoto (inbred control), and Wistar (outbred control) rats. During the set shift phase, adolescent SHR needed more trials and had a longer latency to reach criterion, made more regressive errors and trial omissions, and exhibited slower and more variable lever press reaction times. d- Amphetamine improved performance only in SHR by increasing choice accuracy and decreasing errors and latency to criterion. In adulthood, SHR self-administered more cocaine, made more cocaine-seeking responses, and took longer to extinguish lever responding than control strains. Adolescent d-amphetamine did not alter cocaine self-administration in adult rats of any strain, but reduced cocaine seeking during the first of seven reinstatement test sessions in adult SHR. These findings highlight utility of SHR in modeling cognitive dysfunction and comorbid cocaine abuse in ADHD. Unlike methylphenidate, d-amphetamine improved several aspects of flexible learning in adolescent SHR and did not increase cocaine intake or cue reactivity in adult SHR. Thus, adolescent d-amphetamine was superior to methylphenidate in this ADHD model
Reply: 99mTc-labelled Stealth liposomal doxorubicin (Caelyx®) in glioblastomas and metastatic brain tumours
British Journal of Cancer (2002) 86, 660–661. DOI: 10.1038/sj/bjc/6600094 www.bjcancer.co
Wigner-Poisson statistics of topological transitions in a Josephson junction
The phase-dependent bound states (Andreev levels) of a Josephson junction can
cross at the Fermi level, if the superconducting ground state switches between
even and odd fermion parity. The level crossing is topologically protected, in
the absence of time-reversal and spin-rotation symmetry, irrespective of
whether the superconductor itself is topologically trivial or not. We develop a
statistical theory of these topological transitions in an N-mode quantum-dot
Josephson junction, by associating the Andreev level crossings with the real
eigenvalues of a random non-Hermitian matrix. The number of topological
transitions in a 2pi phase interval scales as sqrt(N) and their spacing
distribution is a hybrid of the Wigner and Poisson distributions of
random-matrix theory.Comment: 12 pages, 15 figures; v2 to appear in PRL, with appendix in the
supplementary materia
Pengaruh Penggunaan Model Pembelajaran Kooperatif Tipe Group Investigation (Gi) Terhadap Motivasi Belajar Dan Pemahaman Konsep Biologi Siswa SMA Negeri 2 Banjar
Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan model pembelajaran kooperatif tipe group investigation (GI) dan model pembelajaran konvensional terhadap motivasi belajar dan pemahaman konsep Biologi siswa. Rancangan eksperimen penelitian adalah “Non-Randomized Post-Test Only Control Group Design”, dengan melibatkan dua kelas. Polpulasi penelitian adalah siswa kelas X SMA Negeri 2 Banjar tahun pelajaran 2013/2014. Sampel diambil dari delapan kelas dengan tehnik Simpel Random Sampling. Data dianalisis dengan menggunakan statistik deskriptif dan MANOVA (Multivariat of Analisis Variance) dengan bantuan SPSS 17.0 For Windows dengan taraf signifikansi 5%. Hasil penelitian menunjukkan bahwa (1) terdapat perbedaan yang signifikan motivasi belajar dan pemahaman konsep Biologi antara siswa yang belajar dengan model pembelajaran kooperatif tipe group investigasi dengan siswa yang belajar dengan model pembelajaran konvensional (2) terdapat perbedaan yang signifikan motivasi belajar siswa yang belajar dengan model pembelajaran kooperatif tipe group investigasi dan siswa yang belajar dengan model pembelajaran konvensional, (3) terdapat perbedaan yang signifikan pemahaman konsep Biologi siswa yang belajar dengan model pembelajaran kooperatif tipe group investigasi dan siswa yang belajar dengan model pembelajaran konvensional. Kata Kunci : Model Pembelajaran Kooperatif tipe Group Investigation, Pemahaman konsep, dan Motivasi Belajar. The research was aimed at investigating the effect of the use of cooperative learning model of Group Investigation type (GI) and conventional learning model toward students' learning motivation and students' Biology comprehension concept. The design of experimental research was “Non-Randomized Post Only Control Group Design “, by involving two classes. The population of the research was class X of SMA Negeri 2 Banjar in the academic year 2013/2014. The sample was taken from eight classes by Simple Random Sampling technique. The data was analyzed by using descriptive statistics and MANOVA (Multivariat of Analysis Variance) assisted by SPSS 17.0 for windows with the significance level 5 %. The result of the research showed that (1) There was a significant difference of students' motivation and students' Biology comprehension concept between the students who studied using cooperative learning model of Group Investigation (GI) and students who learned by using conventional learning model. (2) There was a significant difference of students' motivation between the students who studied using cooperative learning model of Group Investigation (GI) and students who learned by using conventional learning model. (3) There was a significant difference of students' Biology comprehension concept between the students who studied using cooperative learning model of Group Investigation (GI) and students who learned by using conventional learning model
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Graphene-polyelectrolyte multilayer membranes with tunable structure and internal charge
One great advantage of graphene-polyelectrolyte multilayer (GPM) membranes is their tunable structure and internal charge for improved separation performance. In this study, we synthesized GO-dominant GPM membrane with internal negatively-charged domains, polyethyleneimine (PEI)-dominant GPM membrane with internal positively-charged domains and charge-balanced dense/loose GPM membranes by simply adjusting the ionic strength and pH of the GO and PEI solutions used in layer-by-layer membrane synthesis. A combined system of quartz crystal microbalance with dissipation (QCM-D) and ellipsometry was used to analyze the mass deposition, film thickness, and layer density of the GPM membranes. The performance of the GPM membranes were compared in terms of both permeability and selectivity to determine the optimal membrane structure and synthesis strategy. One effective strategy to improve the GPM membrane permeability-selectivity tradeoff is to assemble charge-balanced dense membranes under weak electrostatic interactions. This balanced membrane exhibits the highest MgCl2 selectivity (∼86%). Another effective strategy for improved cation removal is to create PEI-dominant membranes that provide internal positively-charged barrier to enhance cation selectivity without sacrificing water permeability. These findings shine lights on the development of a systematic approach to push the boundary of permeability-selectivity tradeoff for GPM membranes
Pengaruh Penerapan Model Pembelajaran Kooperatif Teknik Tutor Sebaya Terhadap Hasil Belajar Tik Ditinjau Dari Motivasi Berprestasi Pada Siswa Kelas VI SD Muhammadiyah 2 Denpasar
Penelitian ini bertujuan untuk mengetahui perbedaan hasil belajar TIK antara siswa yang mengikuti Metode pembelajaran kooperatif teknik tutor sebaya dengan model pembelajaran konvensional ditinjau dari motivasi berprestasi siswa serta interaksi antara model pembelajaran dengan motivasi berprestasi. Populasi dalam penelitian ini adalah siswa kelas VI SD Muhammadiyah 2 Denpasar. Penelitian ini menggunakan rancangan post test only control group design. Teknik sampling yang digunakan adalah: random sampling secara bertahap. Hasil penelitian menunjukkan bahwa (1) terdapat perbedaan hasil belajar TIK antara siswa yang mengikuti Model Pembelajaran Teknik Tutor Sebaya dengan siswa yang mengikuti model pembelajaran konvensional (FABhitung = 43,129 > dari Ftabel sebesar 3,99). (2) terdapat pengaruh interaksi antara model pembelajaran dan motivasi berprestasi terhadap hasil belajar TIK siswa kelas VI SD Muhammadiyah 2 Denpasar (FABhitung = 114,65 yang ternyata lebih besar dari Ftabel untuk taraf signifikansi 0,05 sebesar 3,99, (3) pada kelompok siswa yang memiliki motivasi berprestasi tinggi terdapat perbedaan hasil belajar TIK antara siswa yang mengikuti Model Pembelajaran Teknik Tutor Sebaya dan siswa yang mengikuti pembelajaran konvensional (Qhitung = 17,275 > Qtabel = 4,02 ), dan (4) pada kelompok siswa yang memiliki motivasi berprestasi rendah terdapat perbedaan hasil belajar TIK antara siswa yang mengikuti Model Pembelajaran Teknik Tutor Sebaya dan siswa yang mengikuti pembelajaran konvensional siswa kelas VI SD Muhammadiyah 2 Denpasar (Qhitung = 4,14 > Q-tabel = 4,02).Kata Kunci : hasil belajar TIK, model pembelajaran kooperatif, motivasi berprestasi, teknik tutor sebaya This thesis aims at investigating the difference in IT learning outcome between students following cooperative learning model type peer-tutoring and those following conventional model viewed from students' achievement motivation and interaction between learning model and learning motivation. The population of this study was sixth grade students of Muhammadiyah 2 Denpasar. The research design used was post test only control group design. The sampling technique used was random sampling. The results show that (1) there is a difference in IT learning outcome between students following cooperative learning model type peer-tutoring and those following conventional model (Fobs = 43.129 > Fcv = 3.99). There is an interactional effect between learning model and learning motivation on IT learning outcome of sixth grade students of Muhammadiyah 2 Denpasar (Fobs = 114.65 > Fcv = 3.99). (3) for group of students having high achievement motivation, there is a difference in IT learning outcome between students following cooperative learning model type peer-tutoring and those following conventional model (Qobs = 17.275 > Qcv = 4.02). (4) for group of students having low achievement motivation, there is a difference in IT learning outcome between students following cooperative learning model type peer-tutoring and those following conventional model (Qobs = 4.14 > Qcv = 4.02)
Pengaruh Model Pembelajaran Quantum Terhadap Hasil Belajar Tik Siswa Kelas VII SMP N 3 Mendoyo Dengan Mempertimbangkan Gaya Berpikir Siswa
Tujuan utama penelitian ini adalah untuk mengetahui pengaruh penerapan model pembelajaran kuantum terhadap hasil belajar TIK siswa sebelum dan setelah pengendalian variabel gaya berpikir dan kontribusi gaya berpikir terhadap hasil belajar TIK. Penelitian ini merupakan eksperimen semu dengan menggunakan rancangan The Posttest-Only Control Group Design dengan melibatkan sampel sebanyak 72 orang peserta didik kelas VII SMP Negeri 3 Mendoyo. Sampel penelitian diambil dengan menggunakan Random Sampling. Instrumen penelitian yang digunakan dalam mengumpulkan data ada dua yaitu tes hasil belajar TIK dan tes gaya berpikir. Data yang diperoleh dianalisis menggunakan anava satu jalur. Hasil analisis data menunjukkan sebagai berikut, Pertama, penerapan model pembelajaran kuantum berpengaruh terhadap hasil belajar TIK, nilai sig. lebih kecil dari taraf signifikansi (sig. = 0,000 < α=0,05). Kedua, penerapan model pembelajaran kuantum tetap berpengaruh positif terhadap hasil belajar TIK walaupun telah diadakan pengendalian gaya berpikir, nilai sig. adalah 0,037, lebih kecil dari α = 0,05 (sig. = 0,037 < α = 0,05). Ketiga, terdapat kontribusi gaya berpikir siswa secara keseluruhan yang signifikan sebesar 57,3% terhadap hasil belajar TIK siswa. Hasil penelitian ini memberikan indikasi bahwa penerapan model pembelajaran kuantum dan gaya berpikir memberikan pengaruh positif terhadap hasil belajar TIK. Kata Kunci : gaya berpikir , hasil belajar TIK, model pembelajaran kuantum This research aims at investigating the effect of quantum learning model on information and technology learning achievement of students before and after the control of thinking style variable and its contribution on information and technology learning achievement. It was a quasi-experiment of the posttest only control group design with the sample of 72 seventh grade students of SMP N 3 Mendoyo which was taken using random sampling technique. The instruments used were on information and technology learning achievement and learning style test. The data were analyzed using one-way Anova. The result of the research shows: first, the implementation of quantum learning affects significantly on information and technology learning achievement (sig. = 0,000 < α=0,05). Second, after learning style was controlled, the implementation of quantum learning affects significantly on information and technology learning achievement (sig. = 0,037 < α = 0,05). Third, there is a significant contribution of students\u27 thinking style of 57,3% on students\u27 information and technology learning achievement. These results indicate that the implementation of quantum learning and students\u27 thinking style affect positively on information and technology learning achievement
Response of selected hormonal markers during training cycles on indian female swimmers
The present study was taken up to monitor the fluctuations of the hormones testosterone, cortisol and T/C (Testosterone/Cortisol) ratio concentrations during the three phases of training namely preparatory phase, pre-competitive phase and competitive phase in Indian female swimmers. Blood samples were collected at the completion of each phase to study the impact of training on these hormones. Our results reveal that the testosterone and T/C ratio significantly decreases whereas cortisol increases in the subsequent periodised cycle and it was due to the intensity and volume of training. Our study concludes that the intensity and volume of training has effects on these hormones and also, a swimmer with higher testosterone, lowest cortisol and highest T/C ratio has the highest percentage difference of performance record between the preparatory and competitive phase. Hence, monitoring of these hormones is essential to avoid overtraining and to enhance the performance of the swimmers
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